Receiver



f s. E. WITT Feb. 10. 1925. l

'RECEIVER 'Filed Jan. 27, 1921 Patented Feb. 10, 1925.

UNITED sfraras tame SAMUEL E. WITT, @F CHAG, EELNIS.

Application 'mea January a?, resi.

My invention relates to receivers and has to do more particularly withreceivers ot the so-called loud speaking; type. l

One ot the features ot my invention is the provision of a diaphragmoperatively connected to an armature pivotally associated with thereceiver electromagnetand with the diaphragm normally flexed preferablyb v means of a spring tending to press it toward the pole-piece of theelectro-magnet. Thus the diaphragm is under a. normal dexure by means otthe spring with the armature thus held losest to the pole-piece ott theelectromagnet. li have 'found that with my improved device the diaphragmis vihrated so as to produce a more natural voice tone, and this isparticularly true on the high notes where used for repeating the musicas from phonogra phs. The reproduction comes true to pitch throughoutthe normal range, not a lower pitch as heretofore.

This is brought about, l believe, due to the flexed arrangement or thediaphragm and the cooperating parts, of the'electro magnet connectedtherewith. The diaphragm is thus held under continuous tension andvibrates truer to the variations in magnetic pull of the electromagnet,than where the'diaphragm is free to partake of a greater amplitude ofvibration and thus more tree to vibrate out of tune with the magneticvariations.

lf or a better understanding ot my invention reference is to he had tothe accompany-- ing drawing in which" Fig. l is a transverse sectionthrough my improved receiver along the. line 1--1 of wie e; i

Fig. 2 is' a bottom view of Fig. l; Fig. 3 is a top or plan view of Fig.l; Fig. l is a transverse section along the lin.; 4-4 0f Fig. 3;

ancnrvnn.. i

rial Le. Mfw.

Fighl' is a perspective view of the armature'faatl a part ot theconnector extending:

.to the "diaphragm,

l4`i9;,`l 6 is the mounting: block andspring which act upon the armatureand dialid phragm to elef-t a normal tlexure thereof,

and

Fig. 7 is ad'etail view ol the pole-piece. Referring now more in detailto the pre# fel-red lform of my invention as shown herein, it comprisesa diaphragm mounting which includes a `front plate 8 having; a

threaded portion 9 to which a horn l0 is threaded. firing" 1l is securedto the 'front 'plate 8 by means of screws 12 in order to clamp thediaphragm 13 between the usual yieldable elements 14 which arepreferably small rubber tubes. l also insert a vibration reducing blockl5 preferably of glass between the diaphragm and' frontplate 8.

Secured to the ring ll is a` bridgepiecc 'i6 fastened by means01E/screws as shown by the dot-ted lines in Fig. 1. 'This bridge-piece16 carries insulated binding posts 17-18 which receive the conductors19-20 leadingr from the transmitter 21 andbattery 22. Of course, it isto he understood that the device is not limited use in the particularcircuit illustrated.

. Connected to the diaphragm 13 is an actuating means in the 'term ci anelectromagnet having a circular helix 23 supported upon a core 24 whichacts as a continuation oi the heel-piece 25 and is integral with thethreaded stud 24". The helix is preferably made up of insulated copperwire, loclcstitched with silk thread, and then pressed over the core,the stitching acting as additional insulation between the helix, and thecore and heel-piece. The electromagnet 23 is secured to the mountingplate 26 by means 'of this stud 2li which is inserted through the holein mounting 26 and into the sleeve 27. Between the sleeve 27 and plate26 is secured a leat spring 28 in order to firmly hold the mounting 2Gand its parts in adjusted position. This `adjustment is effected bytheturning or' the screw 29 which is threaded into the rod 27.

ln order to actuate the diaphragm byA points such as at adjustinadyustablv connected with the diaphragm by means o the. screw eye 31which passes through the threaded plates 32, 33 placed upon oppositesides of the mica diaphragm and securely clamping the same. Thisscrew-'eye is hooked over a pin end ot the armature 30 at a point beyondthe core 24 so that there is a slight amplification of movement of thediaphragm. That is, the diaphragm has a greater amplitude of vibrationthan the vibration of the armature at the Core. The pivoting endl of thearma- I ture 30 rests upon the 11p-right of the member 25 and ahuts thebracket 34 which is secured to the Lplate 26. This bracket. 34 has acentral portion struck back from the upright so that a securing meansfor thearma-l lure ymay be passed through the small hole 235 and aroundthis struck bark portion, this securing means being in the form of atine silken cord.

In order to secure a proper cooperation of the electroinagnet anddiaphragm I use tension 'means to normally flex the diaphragm and holdthe armature, in the form of a ,leaf spring 36 which presses against thearmature at a point preferably oppositel edge pivot 41 which engages thetl-shaped groove 42 in the block. New in order to adjust the block andthereby vary the 'tension of the spring 36, the free end of the blockcarries a screw-eye 43 whichI passes through the plate 26 and isengagedby the thumb-nut 44.` It will thus be seen as the nut 44 isrotated block S7 rotates 4on its pivot and may thus vary the tension ofthe spring 36 thereby securing the proper horlmal deiiection ofthediaphragm.

In adjusting the device the armature is connected to the diaphragm bymeans of the screw eye 3].. Then by means of the adjusting nuls Q9 and44 the tension of springfhi and adjustment of armature 30 is `varieduntil the desired air-gap between the arn'iature and core is secured anda suilicient deflection of the diaphragm to secure suitable operationthereof.

It will be noted .that the electroma net, armature and tension springwith its adjustin means are mounted as an adjustable unit', this being'of great advantage in that adjustmentr may be effected at the various ordiaphragm without a acting the other nut 44, Vvnut 29 readme parts.'lhat 1s, the adjustments may be made independently of each other.-

In the use of the device ou a low Voltage such as from about 6 to i)volts.' I have gotten excellent'results with a coil having a resistanceof about three ohms with approximately 20() turns of about thirty-twosingle silk wire. lVheu connected up with the 0rdinaiv local batterytransmitter of about ten to twenty ohms resistance excellent loudspeaking qualities were secured.

'lhe device has a-lso been particularly useful for loud reprodiu-.tionof phonograplue music wherein a suitable transmitter is placed insidethe phonograph horn and then connected to the' receiver as shown inFig. 1. 0n reproducing the voice on my im.

proved direct current receiver. when connected to the phonograph asreferred to, 1t.

produces a more natural voice tone` especially on the high notes. Itcomes true to pitch throughoiu the entire reproduction, not a lowerpitch as heretofore. Heretofore where loud speaking receivers of theperma nent magnet type have been used for phonographic reproduction, sofar as I am aware. the reproduction was of a lower pitch so yeo that atenor sounded more like a, baritone.

This I have overcome by the device shown and. claimed herein.

thus the diaphragm underrgreetest delico-f tion. As soon as thetransmitter is operated the resistance of the circuit through thereceiver coil is increased so that the diaphragm falls away 'from theelectromagnet. Also as the pitch of the actuating tone increases, thetransmitter vibrates more and the resistance increases still furtherthus permitting a further recession of the diaphragm. At this time. ofcourse. it is farthest away from the electromagnet and at a time whenthi nest work is expected because the. high no es are being transmitted.Also it is to be noted that as an armature recedes from the pole-piecesof the eleetromagnet, the pull decreases directly with the S uare of thedistance. Where no externa tension is brought to bear upon thediaphragm, et the time of transmission of the highest notes andwith thediaphragm furthest from the eleotromagnet, the Weakest actuating currentis operatingupon the diaphragm and also at. a time when it is free topartake ana waarna aise of greet volume. holding' true to a grenierrange `than I have heen hereiofore able io secure.

l claimi. in a receiver, a diaphragm, an elecf' troniagnei, a normaliynon-polarized armature for the eleotroniagnet rigidly cenneeied te thediaphragrri, and a Spring eating' against ilie armature and mnvahletherewith and normally iexing 'the diaphragm and armature teward theeleetromagnet.

in a receiver, a. diaphragm and meuniingg, and a uniiadjustably mountedrelative n:- rlie diaphragm, said unit comprising an elect nagnei; and.non-polarized armature eonneri-ed to ille diephagm and spring aeting;unen the arinaure and ieaing the diaph c i and means ior edyuating theto 1 izhe upon the armature and nei-mai ileaure ef the diaphragm.

:5. in a receiver', a diaphragmand menne ing, a iiridge irrediy secured'to the diaphragm nannntiep, a unit comprising en electroinagnet an(armature connected to the diaphragnn and single mounting carry ing theeieetromagnet and armature, and nie-.ane 'for adiaetabiy supporting said'enit mounting upon the 'hridge whereby adjustimeni: of the singlemounting will simultaneously adjust the magnet and armature relative tethe diaphragm.

ii. ln a receiver, a diaphragm and mounting', a bridge secured to thediaphragm mounting, a unit comprising an eleetromag' nel', and armatureeonneeted to the diaphragm and an adjnetahie spring acting up en thearmature and dering the diaphragm, for adjustahiy' supporting sai-fi:mit unen said bridge.

in a direct current yreeeiver, a diaphragm, an oleetreinagnet andnon-polar ized ainiaiiire connect/ed with the diaphragm nml positionedrelative thereto so that the diaphragm and armature vibrateSubstantially parallel and the direction ot' motion of the diaphragm andarmature coincide, resilient mechanical means acting upon the armatureand diaphragm eo as to press the arl'nature toward the pole ieee of themagnet and normally Hex t e diaphragm suilieiently te maintain the amiitude of the operating vibrations of the iaphragrm within the concaveformed by the iicxure.

6. In a receiver. a diaphragm, a supporting bridge, a mounting'adjust-ably carried by the bridge piece. an electromagnet, an armaturecarried hy the mounting, means for operatively connecting the armatureto 'the diz'tphragm, and a 'tension spring tending to presa ihearn'iature toward the electroniagnet adjusfahly carried oy themounting'.

T. lu a receiver, a diaphragm, an4 electromagnei' and armaturei'fperatively Connected to the ,l{ifiphragm. a mounting fier theeleci'ronaifnet and armature, a block pivotally attached ai ene end tothe mounting and carrying a. springn ai' the other end for plaeing:icnaien upon the armature, and an adjus'ring' screw .ffonnecied to anintermediate pertion of the hief-ir so as'to move the bloei: io vary theensioi" of the spring upon the armature.

53. ln a rfgeivcf. a diaphragm, an eleetifoniagnet and armatureoperatively conneared to the diaphragm, a mounting im' theelectrouiagnet and armature, a lever 'pivvw otally attached to themounting and carry ing' a spring', said spring placing a yieldingriension upon the armature "whereby the spring' moves with the operatingmovement@ of the armature, and an adjusting screw conneeied to ihe leverso as to move the lever io vary the tension action of the spring uponthe armature.

9. in a dirent current receiver, a dia pliragm, an electromagnet, anarmature having' adjustment reiative te the eleetromagnet io vary its'air gap and operatively Connected by a rigid link to the diaphragm, aresilient member for placing tension to give a Substantial normaliiexure to the diaphrag, and means for varying" the tension upon thediaphragm at different air gaps of the eleci'roniag'net and armature.

10. ln a. direct current receiver, a daphragm, an eiectrornagnet, anarmature having adjustment relative to the electromagnet to vary ita airgrap and operatively connected hy a rigid. link to the diaphragm, areailient member Een placing tension to frive a Substantial normaliieizure to the diaphragm, means for varying tension upon the diaphragm,and means for varying the air gap for different tensions on `the dia- Inwitness whereof. I hereuntoeuhserihe my name this 19th day of January,A. D., 1921. y

SAlWUEL E. WiTT.

